This invention relates to a particulate material suitable for selectively removing metal cations from aqueous solutions. The invention further relates to a process for producing the material of the invention and to the use of the material of the invention.
Materials for removing ionic components from aqueous solutions are known. Thus, ion exchange resins are utilized for removing ions from aqueous solutions. Low selectivity, decreasing activity and leaching out of the resin into the aqueous solution are undesired side effects when these resins are used.
In U.S. Pat. No. 4,500,494, a material for removing metal cations from water is disclosed which contains a water-insoluble chelate former, which is either liquid or is dissolved in a water-insoluble solvent, in microcapsules which have a shell of polyurea or urea-formaldehyde. A disadvantage of this material is based on the fact that the solvent in the microcapsules comprises optionally chlorinated aromatic or chlorinated aliphatic hydrocarbons. Continuous diffusion of the solvent through the polymer shell is unavoidable.